| 1 | W & T Offshore, Inc. | Houston, TX 77057 | Oil & Gas Operator | Oct 2025 |
| 2 | W. W. F. Oil Corporation | | Oil & Gas Operator | Dec 1999 |
| 3 | Wagner Oil Company | Fort Worth, TX 76102 | Oil & Gas Operator | Oct 2025 |
| 4 | Wainoco Oil & Gas Company | Houston, TX 77024 | Oil & Gas Operator | Dec 2005 |
| 5 | Wallace Operating Company | | Oil & Gas Operator | Sep 1986 |
| 6 | Walter Oil & Gas Corporation | Houston, TX 77002 | Oil & Gas Operator | Oct 2025 |
| 7 | Wayman W. Buchanan | | Oil & Gas Operator | Feb 1986 |
| 8 | Weaver Exploration Company | | Oil & Gas Operator | Jun 1991 |
| 9 | Weeks Exploration Company | Houston, TX 77063 | Oil & Gas Operator | Aug 1995 |
| 10 | Wes-Tex Drilling Company | Abilene, TX 79604 | Oil & Gas Operator | Jan 2000 |
| 11 | White Oak Operating Company LLC | Houston, TX 77077 | Oil & Gas Operator | Oct 2025 |
| 12 | Whiting Oil And Gas Corporation | Houston, TX 77002 | Oil & Gas Operator | Oct 2025 |
| 13 | Whiting Petroleum Corporation | Denver, CO 80290 | Oil & Gas Operator | Jan 2025 |
| 14 | Whitney Oil & Gas, LLC | | Oil & Gas Operator | Jan 2025 |
| 15 | WHK, Inc. | | Oil & Gas Operator | Oct 1993 |
| 16 | Williams Exploration Company | | Oil & Gas Operator | Dec 1986 |
| 17 | Windfohr Oil Company | | Oil & Gas Operator | May 1980 |
| 18 | Wintershall Corporation | | Oil & Gas Operator | Oct 1989 |
| 19 | Wintershall Oil & Gas Corp | Houston, TX 77027 | Oil & Gas Operator | Jul 1989 |
| 20 | Woods & Deas-Dobie | | Oil & Gas Operator | Aug 1983 |
| 21 | WRT Energy Corporation | Oklahoma City, OK 73118 | Oil & Gas Operator | May 1998 |